Evaluation of the Neuroprotective Effect of Sirt3 in Experimental Stroke
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Sirtuins (Sirt) are a family of NAD+ dependent histone deacetylase (HDAC) proteins implicated in aging, cell cycle regulation, and metabolism. These proteins are involved in the epigenetic modification of neuromodulatory proteins after strokevia acetylation/deacetylation. The specific role of Sirt3, a mitochondrial sirtuin, in post-stroke injury has been relatively unexplored. Using male Sirt3 knockout (KO) mice and wild-type littermates (WT), we show that Sirt3 KO mice show significant neuroprotection at 3 days after ischemia/reperfusion (I/R) or stroke injury. The deacetylation activity of Sirt3, measured as the amount of reduced acetylated lysine, was increased after stroke. Stroke-induced increases in liver kinase 1 (LKB1) activity were also reduced in KO mice at 3 days after stroke. On further investigation, we found that the levels of Sirt1, another important member of the Sirtuin family, were increased in the brains of Sirt3 KO mice after stroke. To determine the translational relevance of these findings, we then tested the effects of pharmacological inhibition of Sirt3. We found no benefit of Sirt3 inhibition despite clear evidence of deacetylation. Overall, these data suggest that Sirt3 KO mice show neuroprotection by a compensatory rise in Sirt1 rather than the loss of Sirt3 after stroke. Further analysis reveals that the beneficial effects of Sirt1 might be mediated by a decrease in LKB1 activity after stroke. Finally, our data clearly demonstrate the importance of using both pharmacological and genetic methods in pre-clinical stroke studies.
KeywordsSirtuins Stroke Neuroprotection Deacetylase LKB1
This work was supported by National Institutes of Health grants R01NSO77769 (to Louise D McCullough) and an AHA postdoctoral fellowship 14POST20380612 (to Rajkumar Verma).
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflict of interest.
All animal protocols were approved by the University’s Institutional Animal Care and Use Committee at UConn Health, Farmington, CT, and were performed in accordance with National Institutes of Health guidelines.
- 7.Kim HJ, Rowe M, Ren M, Hong JS, Chen PS, Chuang DM. Histone deacetylase inhibitors exhibit anti-inflammatory and neuroprotective effects in a rat permanent ischemic model of stroke: multiple mechanisms of action. J Pharmacol Exp Ther. 2007;321(3):892–901. https://doi.org/10.1124/jpet.107.120188.CrossRefPubMedGoogle Scholar
- 15.Lan F, Cacicedo JM, Ruderman N, Ido Y. SIRT1 modulation of the acetylation status, cytosolic localization, and activity of LKB1. Possible role in AMP-activated protein kinase activation. J Biol Chem. 2008;283(41):27628–35. https://doi.org/10.1074/jbc.M805711200.CrossRefPubMedPubMedCentralGoogle Scholar
- 20.Verma R, Harris NM, Friedler BD, Crapser J, Patel AR, Venna V, et al. Reversal of the detrimental effects of post-stroke social isolation by pair-housing is mediated by activation of BDNF-MAPK/ERK in aged mice. Sci Rep. 2016;6(1):25176. https://doi.org/10.1038/srep25176.CrossRefPubMedPubMedCentralGoogle Scholar
- 21.Huang W, Huang Y, Huang RQ, Huang CG, Wang WH, Gu JM, et al. SIRT3 expression decreases with reactive oxygen species generation in rat cortical neurons during early brain injury induced by experimental subarachnoid hemorrhage. Biomed Res Int. 2016;2016:8263926–9. https://doi.org/10.1155/2016/8263926.CrossRefPubMedPubMedCentralGoogle Scholar
- 35.Jackson JG, Pereira-Smith OM. Primary and compensatory roles for RB family members at cell cycle gene promoters that are deacetylated and downregulated in doxorubicin-induced senescence of breast cancer cells. Mol Cell Biol. 2006;26(7):2501–10. https://doi.org/10.1128/MCB.26.7.2501-2510.2006.CrossRefPubMedPubMedCentralGoogle Scholar
- 38.Kim S, Titcombe RF, Zhang H, Khatri L, Girma HK, Hofmann F, et al. Network compensation of cyclic GMP-dependent protein kinase II knockout in the hippocampus by Ca2+-permeable AMPA receptors. Proc Natl Acad Sci U S A. 2015;112(10):3122–7. https://doi.org/10.1073/pnas.1417498112.CrossRefPubMedPubMedCentralGoogle Scholar